Note: Descriptions are shown in the official language in which they were submitted.
CA 02699160 2010-04-07
SYSTEM AND METHOD FOR
FORMING BARBS ON A SUTURE
BACKGROUND
Technical Field
[00021 The present disclosure relates to medical sutures having barbs
formed thereon.
More particularly, the present disclosure relates to a system and method of
forming barbs on
sutures.
Background of Related Art
[00031 Barbed sutures are generally made of the same materials as
conventional sutures
and offer several advantages for closing wounds compared with conventional
sutures. A barbed
suture includes an elongated body that has one or more spaced barbs, that
project from the
surface of the suture body along the body length. The barbs are arranged to
allow passage of the
barbed suture in one direction through tissue but resist movement of the
barbed suture in the
opposite direction. Thus, one advantage of barbed sutures has been the
provision of a non-slip
attribute.
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100041 Barbed sutures are known for use in cosmetic, laparoscopic and
endoscopic
procedures. The number of barbs called for on a particular suture may be
influenced by the size
of the wound and the strength required to hold the wound closed. Like a
conventional suture, a
barbed suture may be inserted into tissue using a surgical needle.
[0005] In some circumstances, a random configuration of barbs on the
exterior surface of
the suture is preferred to achieve optimal wound closure holding for the
particular wound.
However, in other circumstances, where the wound or tissue repair needed is
relatively small, a
reduced number of barbs may be desired. In other circumstances, a two-way
barbed suture is
desirable where the barbs permit passing of the suture in one direction over a
portion of the
suture and barbs permitting passing of the suture in a second direction over
another portion of the
suture to perform a tight closing stitch.
[0006] Various methods of forming barbs on sutures have been proposed
such as
mechanical cutting, laser cutting, injection molding, stamping, extrusion and
the like. Such
methods may be difficult to achieve the desired result with respect to getting
the arrangement of
barbs in a configuration needed for the appropriate procedure and for doing so
in an efficient cost
effective manner. Conventional cutting methods of forming barbs have
significant drawbacks in
their ability to maintain sharpness, move rapidly and have slow manufacturing
cycle time.
[0007] Accordingly, there is a continuing need for a system and method of
forming barbs
on a suture that is less difficult, more effective and economical.
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SUMMARY
[0008] A station for cutting a barb suture is provided. The barb cutting
station includes a
suture transport assembly for supporting a first suture, a first knife
assembly for forming barbs
on the first suture, and a first clamp and position assembly for approximating
the first suture
towards the first knife assembly. The barb cutting station may further include
a first suture
cutting mechanism configured for severing the at least first suture when a
defect is detected. The
station may also include a first visual inspection assembly configured for
detecting defective
barbs.
100091 The suture transport assembly, the first knife assembly and the
first clamp and
positioning assembly may be mounted to a base panel. The base panel may be
mounted within a
cabinet. The first knife assembly may include an ultrasonic mechanism for
ultrasonically
vibrating a blade extending therefrom. The first clamp and position assembly
includes a
gripping assembly for selectively gripping the first suture. The suture
transport assembly may
include an adjustment mechanism. The suture transport assembly may include a
first pair of
rotary motors configured to rotate the first suture along its longitudinal
axis. The suture transport
assembly may include a first tensioning cylinder configured to provide tension
to the first suture.
100101 Also provided is a method of forming a first barbed suture. The
method includes
providing a suture forming station including a suture transport assembly, a
first knife assembly,
and a first clamp and position assembly. The method further includes
positioning a suture on the
suture transport assembly, aligning the suture transport assembly with the
knife assembly,
activating the first knife assembly, advancing the suture transport assembly
while simultaneously
approximating the first clamp and position assembly towards the first knife
assembly to engage
the suture with the first knife assembly to form a barb, and retracting the
first clamp and position
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assembly away from the first knife assembly. Retraction of the first clamp and
position
assembly may cause the deflection of the barb away from a longitudinal axis of
the suture.
[0011] . The barb forming method may further include the step of advancing
the suture
transport assembly relative to the first knife assembly to prepare the suture
for a subsequent
engagement with the knife assembly. The method may also include the steps of
advancing the
suture transport assembly and approximating the first clamp and position
assembly towards and
away from the knife assembly, one or more times to form additional barbs on
the suture. The
suture transport assembly of the barb forming method may be configured to
receive a pair of
sutures.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] Various embodiments of the present disclosure will be described
herein below
with reference to the figures wherein:
[0013] FIG. 1 is a side view of a barbed suture formed in accordance with
the present
disclosure;
[0014] FIG. 2 is a perspective view of a cabinet of a barb cutting
station according to an
embodiment of the present disclosure;
[0015] FIG. 3 is a schematic view of a base panel of the barb cutting
station of FIG. 2;
[0016] FIG. 4 is a perspective view of a suture support assembly of the
barb cutting
station of FIG. 2;
[0017] FIG. 5 a schematic view of a pair of clamp and position assemblies
of the barb
cutting station of FIG. 2 showing their respective locations on the base
panel;
[0018] FIG. 6 is a perspective view of the clamp and position assembly of
FIG. 5;
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[0019] FIG. 7 is a perspective view of a knife assembly of the barb
cutting station of FIG.
2; and
[0020] FIG. 8 is a side sectional view of a barbed portion of the barbed
suture of FIG. 1.
DETAILED DESCRIPTION
[0021] A system and method for forming a barbed suture is herein
described. Referring
initially to FIG. 1, a barbed suture formed in accordance with the method of
the present
disclosure is shown generally as barbed suture 10. Suture 10 is formed from a
monofilament
thread 11, however, it is envisioned that suture 10 may be formed braided
threads, multifilament
threads and other surgical fibers. Although shown having a circular cross-
sectional geometry,
the cross-sectional geometry of thread 11 may be of any suitable shape. For
example, thread 11
may be round, elliptical, square, flat, octagonal, and rectangular. Thread 11
may be formed of
degradable materials, non-degradable materials, and combinations thereof.
Thread 11 may be
formed using any technique within the purview of those skilled in the art,
such as, for example,
extrusion, molding and/or solvent casting.
[0022] Still referring to FIG. 1, barbed suture 10 includes a loop 12
formed on a distal
end 10b thereof. Loop 12 is configured to facilitate attachment of distal end
10b of thread 11
with barb cutting station 100 (FIG. 2). Loop 12 may be formed in any manner
and may be of
any size and configuration. It is envisioned that barb cutting station 100 may
be modified such
that thread 11 may be attached thereto without loop 12. Optionally, barbed
suture 10 includes a
suture needle 14 attached to a proximal end 10a thereof. Needle 14 may be
attached to thread 11
prior to or upon completion of the barb forming process. Formed on thread 11
between loop 12
and suture needle 14 are a plurality of radially spaced barbs 16. As will be
discussed in greater
, õ
õ.
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detail below, barbs 16 may formed in any number, size, configuration, spacing
and/or
orientation.
[0023] With reference now to FIGS. 2-7, a system for forming barbed
suture 10 will be
described and is shown generally as barb cutting station 100. Referring
initially to FIG. 2, barb
cutting station 100 includes a cabinet 102 having a first housing 104, a
second housing 106, and
a control box 108. First housing 104 is configured to receive a base panel
110. Electric
components (not shown) are maintained within second housing 106. Control box
108 is
configured for controlling operation of cutting station 100. Although shown as
a single unit, it is
envisioned that first and second housings 104, 106 and/or control box 108 may
arranged
independent of one another. In this manner, cutting station 100 may be
operated remotely.
[0024] Turning now to FIG. 3, maintained within cabinet 102 (FIG. 2) and
mounted on
base panel 110 are a suture transport assembly 200, a pair of knife assemblies
300, and a pair of
clamp and position assemblies 400. Optionally, mounted to base panel 110 are a
pair of suture
cutting mechanisms 600 and/or a pair of visual inspection assemblies 500.
[0025] With reference still to FIG. 3, suture transport assembly 200 is
mounted to base
panel 110 in an upright position along a track 112. Suture transport assembly
200 is configured
to support a pair of sutures 10 during the barb forming process. Suture
transport assembly 200 is
configured to move linearly along track 112 perpendicular to knife assemblies
300, in the
direction of arrows "A÷.
[0026] Turning now to FIG. 4, suture transport assembly 200 includes a
base member
202, a fixed upper support member 204 and an adjustable lower support member
206. Fixed
upper support member 204 includes a pair of rotary assemblies 210 each.
including a pin
assembly 212 extending therefrom for engaging loops 12 formed on distal ends
10b of respective
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sutures 10. As discussed above, in an alternative embodiment, support member
204 are
configured to engage sutures 10 without the use of loops 12. In this manner,
each of support
members 204 may include a clamp or anchor (not shown) for attachment of distal
ends 10b of
sutures 10 thereto.
[0027] Still referring to FIG. 4, adjustable lower support member 206
includes a pair of
rotary assemblies 220 each including a needle holding assembly 222 extending
therefrom for
engaging proximal ends 10a (FIG. 1) of respective sutures 10. Holding
assemblies 222 may
include a clamp, anchor or other fixation device suitable for attachment with
proximal ends 10 of
sutures 10. Rotary assemblies 220 each further include a tensioning device 223
for tensioning
sutures 10 once sutures 10 have been received between respective pin
assemblies 212 and needle
holding assemblies 222. Tensioning device 223 may be hydraulic, pneumatic,
gravity operated,
spring-load or otherwise configured to provide tension to sutures 10. Lower
support member
206 further includes an adjustment mechanism 225 for adjusting the distance
between lower
support member 206 and upper support member 204. In this manner, suture
transport assembly
200 may accommodate sutures 10 of various lengths. Each of upper and lower
support members
204, 206 further includes a rotary motor 224, 226, respectively, operably
connected to rotary
assemblies 210, 220, respectively, for rotating sutures 10 along longitudinal
axis thereof, in the
direction of arrows "B÷.
[0028] Referring briefly back to FIG. 3, knife assemblies 300 are fixedly
mounted to
base panel 110 adjacent suture transport assembly 200. Knife assemblies 300
are configured for
cutting barbs 16 (FIG. 1) in sutures 10. Turning now to FIG. 5, each of knife
assemblies 300
includes a base 302 and a cutting assembly 304 operably mounted to base 302.
Each of cutting
assemblies 304 include a cutting member 306 extending outwardly therefrom and
include a blade
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308 for cutting barbs in sutures 10. As shown, knife assemblies 300 include an
ultrasonic
mechanism 312 for ultrasonically vibrating blade 308. Alternatively, knife
assemblies 300 may
include a heating element or other suitable mechanism (not shown) for heating
blade 308. By
vibrating or heating blade 308, the force necessary to cut barbs 16 may be
reduced.
[0029] Still referring to FIG. 3, each of cutting assemblies 304
further includes a rotary
mechanism 310 for rotating cutting members 306. Rotary mechanism 310 is
configured to index
blade 308 during the barb forming process to adjust the angle of cut. Blade
308 may further be
rotated at least one-hundred and eighty degrees (1800) such that each surface
of blade 308 may
be used. In one embodiment, rotation of blade 308 occurs only after the
desired number of barbs
16 have been formed along the desired length of sutures 10. Cutting assemblies
304 are mounted
to bases 302 such that cutting members 306 may be advanced, in the direction
of arrows "C". In
this manner, cutting assemblies 222 may be retracted once the barb forming
process is completed
to permit reloading and repositioning of suture transport assembly 200.
Cutting assemblies 304
remain stationary or in a fixed position during the cutting of sutures 10 to
form barbs 16. In this
manner, blades 308 are not moved into contact with the suture, instead clamp
and position
assemblies 400 move suture 10 into contact with blades 308.
[0030] Turning to FIGS. 3 and 6, clamp and position assemblies 400
are securely
mounted to base panel 110 adjacent suture transport assembly 200 and
respective ultrasonic
knife assemblies 300. Clamp and position assemblies 400 are configured for
approximating
sutures 10 towards and away from ultrasonic knife assembly 300. Turning now to
FIG. 6, each
of clamp and position assemblies 400 includes a stationary base 402 and a
moveable carriage
404. Carriage 404 includes a gripper assembly 406 for selectively gripping
suture 10 during the
barb forming process. Gripper assembly 406 includes an anvil portion 408 for
supporting suture
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as carriage 404 is approximated towards cutting member 306 of knife assembly
300 and as
suture 10 engages blade 308.
[0031] With reference back to FIG. 3, visual inspection assemblies 500
are configured
for monitoring the cutting of barbs 16. In the event that a misformed or
defective barb is cut,
visual inspection assembly 500 is configured to signal cutting mechanism 600
to sever the
defective suture, such that that suture may not be used.
[0032] With reference still to FIG. 3, cutting mechanism 600 is
configured for cutting
suture 10 in the event that a defective barb is detected by visual inspection
assembly 500.
Cutting mechanism 600 may fuither be configured for manual actuation by an
operator. Cutting
mechanism 600 may include any device capable of selectively severing suture 10
during the barb
forming process. Cutting mechanism 600 may include a blade 602, or a laser, a
heating element
or other suitable device (not shown).
100331 The operation of the suture cutting station 100 will now be
described with
reference to FIGS. 2-7. Initially, cabinet 102 is opened to access base panel
110. Suture
transport assembly 200 is then adjusted using adjustment mechanism 225 to
configure upper and
lower support members 204, 206 to accommodate sutures 10 of a given length.
Sutures 10 are
next secured to suture transport assembly 200 by hooking loops 12 formed on
distal ends 10b of
sutures 10 about pin assemblies 212 of fixed upper support member 204 and
fastening aimed
proximal ends 10a of sutures 10 within needle holding assemblies 222 of lower
support member
206. Tensioning cylinders 223 within rotary assemblies 220 ensure that sutures
10 are properly
tensioned between pin and needle holding assemblies 212, 222, respectively.
Suture transport
assembly 200 is then positioned such that blades 308 of cutting member 306 are
aligned near
proximal ends 10a of sutures 10.
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[00341 Once suture transport assembly 200 is properly positioned with
respect to
ultrasonic knife assemblies 300, cutting assemblies 304 of knife assemblies
300 are advanced in
the direction of arrows "C" (FIG. 3), such that blades 308 of cutting
assemblies 306 are
positioned outwards of and in close approximation to (but not in contact with)
sutures 10. Knife
assemblies 300 are then activated to cause the ultrasonic vibrating or heating
of blades 308.
Once knife assemblies 300 have been activated, cutting assembly 304 remains
stationary during
the barb forming process and suture transport assembly 200 and clamp and
position assemblies
400 operate in unison to move sutures 10 relative to blade 308 to form barbs
16 (FIG. 1) along
the lengths thereof.
[00351 With reference to FIG. 8, barbs 16 are formed in two steps. A
first portion 22 of
the cut is made at an angle ("13") of from about thirty to about forty degrees
(30 - 40 ) with
respect to the surface of the suture to a predetermined depth. In this manner,
clamp and position
assemblies 400 are approximated towards blades 308 (arrow "D") while suture
transport
assembly 200 advances sutures 10 longitudinally (arrow "A"). The angle of cut
is then adjusted
for the second portion 24 to an angle ("u") of from about two to about eight
degrees (2 - 10 )
with respect to the surface or longitudinal axis of suture 10 by varying the
rate of movement of
clamp and position assemblies 400 and suture transport assembly 200 relative
to each other and
blade 308.
100361 Upon completion of the second cut, clamp and position assemblies
400 are
approximated away from cutting assemblies 304 thereby causing blades 308 to
engage, and thus,
flex barbs 16 outwardly. Sutures 10 are then released from gripper assemblies
406 as clamp and
position assemblies 400 continue to move away from cutting assemblies 304 to
permit suture 10
to be repositioned for the next cut. Suture transport assembly 200 then
advances sutures 10
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relative to cutting assemblies 306 as rotary assemblies 210, 220 rotate
sutures 10 along
longitudinal axis thereof to ready sutures 10 for the next cut. Depending on
the desired
configuration of barbs 16 along a length thereof, rotary assemblies 210, 220
may be configured
to rotate sutures 10 from zero degrees (0 ) thru three-hundred sixty degrees
(360 ) along a length
thereof.
100371 Additional barbs 16 are formed in the manner described above. This
process
continues until barbs 20 are formed along the desired lengths of sutures 10.
Knife assemblies
300 are then retracted to permit suture transport assembly 200 to return to an
initial position.
Sutures 10 are then unloaded and the barb forming process is complete.
[00381 During barb formation, visual inspection assemblies 500 (FIG. 3)
monitor the
characteristics of barbs 16. In the event a barb is detected that does not
conform to the desired
configuration, suture cutting mechanism 600 (FIG. 3) is activated, thereby
severing suture 10 and
terminating the barb forming process.
100391 Barb cutting station 100 may be configured to cut barbs 16 in any
suitable pattern,
for example, helical, linear, or randomly spaced. The pattern may be
symmetrical or
asymmetrical. The number, configuration, spacing and surface area of the barbs
may vary
depending upon the tissue in which barbed suture 10 is used, as well as the
composition and
geometry of the material utilized to form suture 10. Additionally, the
proportions of barbs 16
may remain relatively constant while the overall length and spacing thereof
may be determined
by the tissue being connected. For example, if barbed suture 10 is to be used
to connect the
edges of a wound in skin or tendon, barbs 16 may be made relatively short and
more rigid to
facilitate entry into this rather firm tissue. Alternatively, if barbed suture
10 is intended for use
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in fatty tissue, which is relatively soft, barbs 16 may be made longer and
spaced further apart to
increase the ability of the suture to pip the soft tissue.
[0040] The surface area of barbs 16 may also vary. For example, fuller-
tipped barbs may
be made of varying sizes designed for specific surgical applications. For
joining fat and
relatively soft tissues, larger barbs may be desired, whereas smaller barbs
may be more suitable
for collagen-dense tissues. In some embodiments, a combination of large and
small barbs within
the same structure may be beneficial, for example when a suture is used in
tissue repair with
differing layer structures. Use of the combination of large and small barbs
with the same suture
wherein barb sizes are customized for each tissue layer will ensure maximum
anchoring
properties. In particular embodiments, a single directional suture may have
both large and small
barbs; in other embodiments a bi-directional suture may have both large and
small barbs. The
barbs formed may include geometrical shapes such as round, triangular, square,
oblique,
elliptical, octagonal, rectangular, and flat
[0041] While the above description contains many specifics, these specifics
should not be
construed as limitations on the scope of the disclosure, but merely as
exemplifications of
embodiments thereof. Those skilled in the art will envision many other
possibilities within the
scope of the disclosure as defined by the claims appended hereto.
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